The present disclosure relates to a fixing device fixing a toner image onto a recording medium and an image forming apparatus including the fixing device.
Conventionally, an electrographic image forming apparatus, such as a copying machine, a printer, a facsimile or a multifunction peripheral, includes a fixing device fixing a toner image onto a recording medium, such as a sheet. In the fixing device, a heating roller manner is widely used. The heating roller manner is a manner forming a fixing nip by using a pair of rollers.
However, in order to reduce heat capacity of the fixing device and to shorten warm-up time, transition of a fixing manner from the above-mentioned heating roller manner to a belt manner is progressed. The belt manner is a manner forming the fixing nip by using a fixing belt.
For example, there is the fixing device including the fixing belt, a pressuring member coming into pressure contact with the fixing belt to form the fixing nip, a heat source arranged at the inside in a radial direction of the fixing belt, a nip member arranged so as to sandwich the fixing belt between the nip member and the pressuring member and a supporting member supporting the nip member.
In the fixing device with such a configuration, when the supporting member is arranged between the heat source and the nip member, it is impossible to radiate a radiant heat from the heat source directly to the nip member and it becomes difficult to heat the fixing nip by heat transmission from the nip member. Therefore, when the recording medium takes heat of the fixing nip while the recording medium passes through the fixing nip, it is feared that temperature of the fixing nip is suddenly lowered and the toner image cannot be surely fixed onto the recording medium.